Just pulling tidbits here, don't know if any of them produced your plate. Unfortunately all of these makers appear to have a specific mark or marks. Possibly they produced for other companies? Will keep searching.
http://www.oldcopper.org/anaconda.htm "Anaconda Brass (Canada) started as J.F. Brown’s Copper & Brass Rolling Mills, in 1919, located on Birmingham Street, New Toronto, Ontario. Anaconda acquired the mills soon after in 1922. In its last few years of operations, it was Arrowhead Metals. The plant closed in 1989."
http://www.oldcopper.org/benedict.htm"Benedict Proctor Mfg. Co. Flemish Copper B.P. Co./Flemish Copper. Flemish Copper is probably a style name for the non-silver plated wares of Benedict Proctor Mfg. Co. of Trenton, Ontario, Canada. They began in Toronto in 1913 and relocated to Trenton in 1917. The factory closed in 1982 and was demolished to make way for a park on the Trent River."
http://www.oldcopper.org/UnknownMksL-M.htm"Mitchell, Canada, maker's mark under a fire lighter made from an old 4" shell case. More information will be welcome."
http://www.oldcopper.org/Marks%20u-v.htm "Vetcraft Shops, Toronto, one of several shops set up to employ ex-servicemen after the 1914-18 war. It was active from about 1919 until 1925, initially in College Street, later in an industrial building in Dundas West. Other workshops made items such as furniture and toys."
"Viking Copper, M.S. Co. Canada, more information welcome."
http://www.oldcopper.org/Marks%20L.htm" ‘L’ unknown mark on a handsome hand made fluted copper trophy fruit dish engraved 'RYC' 1935 and bought in Canada."
"Lunenburg Foundry, Lunenberg Foundry & Engineering Limited (LIFE), established in 1891 in Nova Scotia, Canada to supply marine and domestic brassfoundrywork. This mark found under a brass Atlantic lobster that still features in their catalogue of souvenirs."
http://www.oldcopper.org/Marks%20B.htm "Paul Beau, Mountain Street, Montreal, Canada (1871-1949). A metalsmith in Arts and Crafts style, frequently mixing metals in a piece to obtain colour contrasts. Later pieces may not have '& Co."
This coco pot and cream/sugar set are listed on eBay and appear to have the same mark as yours. Both are listed out of Ontario so most likely 'locally' made.
http://cgi.ebay.ie/ED34-VINTAGE-VENETIAN-COPPER-COCO-POT_W0QQitemZ200438172926QQcmdZViewItemQQptZLH_DefaultDomain_2?hash=item2eab0bccfe#ht_4506wt_941http://cgi.ebay.ca/VINTAGE-VENETIAN-COPPER-MILK-SUGAR_W0QQitemZ390173106754QQcmdZViewItemQQptZLH_DefaultDomain_2?hash=item5ad8212242#ht_4569wt_1167